Method of and means for building and reenforcing the walls of tunnels, shafts, and the like



6 Aug. 14, 1934. M. MCALPINE 1,969,811

METHOD OF AND MEANS FOR BUILDING AND REENFORCING THE WALLS OF TUNNELS, SHAFTS, AND THE LIKE Filed Oct. 14, 1932 Patented Aug. 14, 1934 UNITED STATES PATENT OFFICE METHOD OF AND MEANS FOR BUILDING Malcolm McAlpine, London, England Application October 14, 1932,

In Great Britain November 19,

1 Claim.

This invention relates to an improved form of reenforcement for the circumferential joints for the curved walls of tunnels, culverts, shafts, wells, or the like, built of tongued and grooved precast segments.

The object of the invention is firstly to overcome the difiiculties involved in transporting the reenforcement material through the tunnel under construction up to the position where the tunnel is being lined with precast segments and in addition thereto to ensure that the reenforcement shall be definitely located in its proper position to perform its purpose and entirely avoid the risk of improper positioning by the workmen during construction.

It will be recognized that in cases where more or less complete rings have been proposed to be used for reenforcement having a diameter larger than the internal diameter of the tunnel the transport of such rings through the already constructed portion of the tunnel is impossible without distortion and is thus very difficult to carry out and much time and labour is involved in the operation. It will be seen that these difficulties are entirely overcome by the use of this invention.

The invention consists in the specific form of the reenforcement means for the curved walls of tunnels, shafts and the like in which the circular circumferential reenforcement is used of a diameter larger than that of the inside of the tunnel and is in segments which are adapted to abut against stops provided in the circumferential groove of the ring of segmental elements after erection in the predetermined position in the structure which procedure allows the reenforcing members to be easily transported through the portion of the circular tunnel already constructed.

In order that the invention may be the better understood I will now proceed to describe the same in relation to the accompanying drawing, reference being had to the letters and figures marked Serial No. 637,712 1931 thereon. Like letters refer to like parts in the various figures in which:

Figure 1 is a longitudinal section of one form of tunnel construction by way of example showing the disposition of the reenforcement therein.

Figure 2 shows the stiff segmental bar reenforcement disposed in a groove in the segmental elements of the structure in which stops are provided for locating the segmental bars.

Figure 3 is a sectional view of Figure 2.

In accordance with this invention the circumferential reeni'orcement for a segmentally con- 'structed tunnel as shown in Figure 1 consists of a reenforcement bar 0 in segments as shown in Figure 2 the ends of which abut against stops at located in the interlocking grooves e of two or more of the segmental elements forming the ring 1. The segmental elements in which the stops (1 are provided, have a short reenforcing bar g shown in Figure 3 circumferentially disposed extending on each side of each stop d so that when the bars 0 are grouted in the groove 6 it will take up and transmit the stress from one segment of the ring to the other and make good any loss of strength due to the gap in the reenforcing bars where the stop is situated.

I claim:--

In a tunnel, shaft, or the like tubular structure, a wall constructed of rings consisting of longitudinally inter-tongued and grooved segmental elements, a plurality of segments of stifi circularly formed reenforcing bars disposed in the circumferential jointing groove of each complete ring, the ends of said segmental bars being adapted to abut against stops located at intervals in the circumferential jointing grooves, a short reenforcing bar embedded in the segmental element adjacent each stop and over-lapping the ends of said segmental bars, and grouting embedding the segmental bars in the grooves.

MALCOLM MCALPINE. 

